NL2027105B1

NL2027105B1 - Package for preserving respiring produce and method

Info

Publication number: NL2027105B1
Application number: NL2027105A
Authority: NL
Inventors: Rinke Antony Groeneweg Bastiaan
Original assignee: Perfo Tec B V
Priority date: 2020-12-14
Filing date: 2020-12-14
Publication date: 2022-07-08

Abstract

A package for preserving respiring produce contained in the package, in particular vegetables, fruit, herbs, spices and/or flowers, and an associated method are provided. The package defines a package volume for containing a portion of the produce and a package atmosphere, and comprises a packaging material, in particular a polymer film (lA), provided with one or more perforations (3) enabling gas exchange with the atmosphere surrounding the package (1) to form the package into a Controlled Atmosphere Package (CAP). The package has a package carbon dioxide transmission rate (COjĲgaá) and a package oxygen transmission rate (ogngaa) and a package transmission ratio Bpmk = COzTRmmk / OzTRmmk of at least 1,5, preferably at least 2, more preferably at least 3, still more preferably at least 4, such as 5 or more.

Description

32755-Fe/lf Package for preserving respiring produce and method

TECHNICAL FIELD The present disclosure relates to a package for preserving respiring produce contained in the package, in particular vegetables, fruit, flowers and herbs, comprising a packaging material, in particular a polymer film, provided with one or more perforations enabling gas exchange, in particular the exchange of oxygen and carbon dioxide, with the outside atmosphere surrounding the package. The invention further relates to a method for manufacturing such a package.

BACKGROUND Shelf life of natural products is of interest to producers, sellers, re-sellers and consumers alike. In the case of food stuffs, like vegetables, fruit, herbs and/or spices, taste, flavour, ripeness and/or structural properties {e.g. firmness) are particularly relevant, as well as inhibiting decay processes and/or growth of pathogens. In the case of flowers, particular concern is the so-called vase life, the time cut flowers and/or flowers in a bouquet retain acceptably pleasing appearance and/or fragrance on display. Typically, the vase life is a few days up to about two weeks at most. Shelf life and vase life are affected by initial produce quality and by conditions of storage and/or transport. Natural produce such as flowers, vegetables, fruits and/or herbs tend to respire after being harvested, involving inter alia to a consumption of oxygen and a generation of carbon dioxide. The respiration continues for prolonged periods, in particular if the produce has undergone little to no processing, e.g. having been washed and possibly peeled and/or chopped up, but otherwise fresh and uncooked. When such produce is packaged, the atmosphere within the package is affected by the respiring produce. Conversely, an atmosphere surrounding natural produce affects the respiration, maturation, aging and/or deterioration of the packed produce. It has therefore become customary to package fresh produce in packages with a modified atmosphere (Modified Atmosphere Package or MAP) or with a controlled atmosphere (Controlled Atmosphere Package or CAP). In MAP the produce is packaged, and an artificial gas mixture is used to establish a distinct interior atmosphere in the package, which may however change later on due to the respiration of the packed produce. In CAP the produce is packaged, and the composition of the package atmosphere is controlled by including an active absorber for an atmosphere component, e.g. an oxygen scavenger and/or by adapting transmission of the packaging material to allow exchange with an exterior atmosphere outside the package, e.d. by perforating the material. Modified- and controlled atmosphere packaging (MAP/CAP) preserve produce quality by reducing the aerobic respiration rate while avoiding anaerobic processes that may lead to adverse changes, e.g. in one or more of colour, texture, flavour and aroma.

Another aspect of fresh and/or respiring produce is, on the one hand, the production of water vapour by the produce and, on the other hand, sensitivity to humidity by the produce and/or live contaminants (e.g. microbes, insects, parasites, fungi, ...). Therefore, humidity of the atmosphere inside a package should also preferably be controlled.

In view of the above, different packages and packaging materials have been developed, e.g. see WO 2016/071922 or WO 2016/003899. It is further noted that various aspects of modified /controlled atmosphere packaging are disclosed in US 7,083,837 and in P.V. Mahajan et al., “An interactive design of MA-packaging for fresh produce”, in: “Handbook of food science, technology and engineering”, Y.H. Hui (ed), CRC Press (Taylor & Francis Group) 2006. Additional aspects related to packaging materials and/or packaging of respiring produce are disclosed in EP 2 294 923, US 2010/221393, WO 2017/220801, US 2010/151166, WO 2018/147736, WO 2009/003675, DE 699 01 477, and in M. Mastromatteo, et al. "A new approach to predict the mass transport properties of micro-perforated films intended for food packaging applications”, J. Food. Eng. 113 (1):41-46 (2012-05-18), DOI: 10.1016/J.JFOODENG.2012.05.029; and M. Scetar, et al, "Trends in Fruit and Vegetable Packaging - a Review", Croatian J. Food Tech., Biotech. Nutr., 5(3-4):69-86 (2010), ISSN: 1847-3423.

However, in view of the ongoing strive to improve produce quality and to prevent spoilage and loss, further improvements are still desired.

SUMMARY Herewith a package for preserving respiring produce and a method of manufacturing a package for preserving respiring produce contained in the package are provided and specified in the appended claims.

In an aspect, a package for preserving respiring produce contained in the package, in particular vegetables, fruit, herbs, spices and/or flowers, is provided.

The package defines a package volume for containing a portion of the produce and a package atmosphere, and comprises a packaging material, in particular a polymer film, provided with one or more perforations enabling gas exchange with the atmosphere surrounding the package to form the package into a Controlled Atmosphere Package (CAP). The packaging material has a carbon dioxide transmission rate CO:TR and an oxygen transmission rate O:TR.

The package has a package carbon dioxide transmission rate CO:TRsac: and an oxygen transmission rate OsTRsacr and a package transmission ratio Bpacr = COsTRpacr / O2TRpack Of at least 1,5, preferably at least 2, more preferably at least 3, still more preferably at least 4, e.g. 5 or more.

Thus the package as a whole provides a high transmission ratio between the transmission rates for oxygen and carbon dioxide.

The CO:TR of the packaging material carbon dioxide transmission rate facilitates escape of carbon dioxide and thus reduces elevating CO; concentration in the package atmosphere, thus reducing or preventing risks of anaerobic decay processes.

Further, CO: may dissolve in water, from which it may re-enter the package atmosphere later on, and with which it may react to form carbonic acid which in turn may affect taste and/or composition of food produce stored in the package.

When the package is closed, e.g. sealed, comprising respiring produce, the oxygen in the package atmosphere is consumed and the oxygen concentration decreases.

Closing a bag may also be done by hand with a closing device (e.g. tie, clip, tape, elastic band, etc.) and/or by folding and/or knotting.

Also or alternatively, the package may be (further) closed by other techniques, e.g. by use of adhesives and/or by welding which may comprise using a hand-held device and/or an automated device which may be comprised in the apparatus.

The package may be closed immediately after filling or produce may be filled in the package and the package being closed after a further treatment step and/or conditioning step, e.g. cooling.

A too-low O:-concentration may accelerate anaerobic decay processes; however, a too high concentration enables prolonged development and aging of the produce.

Both should be prevented.

The oxygen transmission rate O:TR of the package enables an inflow of oxygen into the package atmosphere, preventing total consumption of the oxygen.

An oxygen concentration in a range of typically 1- 10%, preferably 2-8% e.g. 3-7% more preferably 4-63 may be 5 preferred to decelerate aging processes (also known as “putting the produce to sleep”) and maximise shelf life. Such concentrations may be achieved by the one or more perforations forming the package as a CAP. By the one or more perforations the oxygen transmission rate of the package as a whole can be increased.

Fach perforation affects the transmission rate of the package as a whole for oxygen and carbon dioxide. The package transmission ratio Ppack facilitates control over the oxygen concentration and the carbon dioxide concentration in the package atmosphere by perforating the material with the one or more perforations. Thus increased inflow of oxygen and increased outflow of carbon dioxide may be balanced by the perforation (s).

The one or more perforations may be provided as one or more microperforations. The package when formed into the CAP should be devoid of other openings than provided by the one or more perforations for accurate control of the package atmosphere.

It is noted that the open area of microperforations for CAP may affect a water vapour transmission rate of the package as a whole only insignificantly.

The presently provided package transmission ratio Boack, has been surprisingly found to enable reducing the amount of oxygen in the package below that normally acceptable for CAP where higher-than-desired amounts of oxygen must be accepted to prevent unacceptably high levels of CO:. The presently provided package has also been surprisingly found to enable reducing the number of perforations in the package and reducing the amount of oxygen in the package below that normally acceptable for CAP. Reducing a number and/or a size of the one or more perforations facilitates reducing manufacturing costs (in particular one or more of: operations, quality control, meeting tolerances) and possibly increasing robustness of the package.

More importantly, such package enables extending shelf life of respiring produce in CAP packages by several days. This may amount to extending shelf life over 10-30% compared to a present day optimum polymer film.

In more detail, in CAP, the oxygen concentration in the package atmosphere may be lowered to a reduced oxygen concentration in order to slow down aging processes, while at the same time ensuring a minimum equilibrium oxygen concentration. Also or alternatively, the carbon dioxide concentration in the package atmosphere may be controlled to a desired maximum value. Thus, aging, maturation and/or decay are slowed down and in particular anaerobic processes such as bacterial growth are prevented. Generally, it is preferred that the equilibrium oxygen concentration and/or carbon dioxide concentration are reached as soon as possible. For that, a combination of CAP and MAP may be used. For the MAP, the initial package atmosphere may be established at or near the time of closing the package by creating in and/or introducing into the package volume an atmosphere modification gas or -gas mixture differing from the ambient atmosphere.

It is known that different species of produce and different varieties within a produce species exhibit different respiration rates, documented in literature. The total open area of the perforations for CAP should be determined based on the produce (to be) packed and the transmission properties of the packaging material itself; the transmission rate of the package for each substance is formed by the combination of the transmission rate of the packaging material and the transmission rate through the perforations for the respective substance. Thus, the one or more perforations perforation provides a perforation carbon dioxide transmission rate CO:TRpersr and a perforation oxygen transmission rate O:TRpers, such that the package carbon dioxide transmission rate CO:TRpack is the sum of the perforation carbon dioxide transmission rate COzTRperr and the carbon dioxide transmission rate CO:TR of the packaging material: CO;TRpack = CO2TRpers + COsTRmat; and the package oxygen transmission rate O0:TRpacx is the sum of the perforation oxygen transmission rate O:TR err and the oxygen transmission rate OTR of the packaging material: OzTRpac = O2TRpers + Oz2TRmat. The package transmission ratio Back then is Brack = (CO2TRpert + COzTRmat) / (OzTRperr + OzTRmat) .

For prolonged storage, most produce benefit from both a low COs-concentration and a low Oz;-concentration in the package atmosphere, wherein the Oz-concentration is in the range of about 1-10% by volume (“&vol”), preferably in a range 3-7 &vol. In order to maintain such low O:-concentration, the perforation (s) in the package should provide an open area configured to control inflow of oxygen into the package volume, in particular establishing a minimum inflow to prevent anaerobicity and a maximum inflow to ensure the low oxygen concentration slowing down the metabolic processes of the produce (a.k.a. “putting the produce to sleep”). This restriction to the open area of the perforation(s) inherently restricts outflow of CO: from the package through the perforations, considering that perforations are a-selective with respect to O: and CO:: typically the ratio for the flow of C0»:0, for 1 small laser perforation is approximately 1. The perforations in the package therefore determine simultaneously an upper limit for outflow of CO: and inflow of O:. Manufacturing a CAP package thus forces a compromise between on the one hand raising the outflow of CO:, which is desired, and on the other hand raising the inflow of 0;, which is undesired.

A high CO:sTR of the packaging material is therefore beneficial in establishing an improved concentration balance between O: and CO: in the package atmosphere, since this raises the transmission rate for CO: for the CAP package as a whole.

The package atmosphere may define an equilibrium amount of oxygen and an amount of carbon dioxide which together make up less than 20 &vol of the package atmosphere, preferably less than 17 &vol such as less than 15 %vol or even less than 13 %vol.

It has been found that as a rule-of-thumb, for present-day packaging films for fresh respiring produce, generally in CAP the amounts of 0; and CO: together make up about 21-23 %vol of the package atmosphere ({amount O:} + {amount CO:} = ca. 21-23 &vol of the package atmosphere). In the presently provided package, the transmission ratio of the package facilitates escaping the aforementioned rule of thumb and achieving both a low concentration of 0: and of CO: in the package atmosphere and a low concentration of CO: in the combined concentration.

Also or alternatively, the packaging material may enclose the package volume defining a packaging surface area Apack. Further, the packaging material may comprise a number (“mm”) of packaging material segments each defining a respective segment surface area Ag: 5 having a respective segment carbon dioxide transmission rate (CO:TRmat 5) and a segment oxygen transmission rate (O:TRmat 5) to an atmosphere surrounding the package. In particular, the sum over all segment surface areas may equal the packaging surface area Apack! Apack = 1 (J = lum) Amar 3. The carbon dioxide transmission rate (CO:TR) of the material may then be the weighted sum of the respective segment carbon dioxide transmission rates (CO:TRmat 35) and the oxygen transmission rate (O:TR) of the material may then be the weighted sum of the respective segment oxygen transmission rates (OzTRmat 3)! COzTR = >(j = 1.m) Amat 3 CO:TRmat 3, and, respectively, O2TR = (J = 1.m) Apgar 3 O2TRpar 3. This allows accommodating and/or accounting for differences between segments.

E.g., the package may comprise one or more of a tray of one material and a lid of another material; a packaging material segment may be of a same material as another segment but having a different thickness affecting the respective segment carbon dioxide transmission rate (CO:TRpac 5) and/or segment oxygen transmission rate (O2TRmst 3); a packaging material segment may have been subject to a particular local treatment; a packaging material segment may be provided with a layer of ink and/or of stickering and/or of other coating, absent in or on another packaging material segment.

Good results for the package may be obtained for example with packaging material comprising films comprising biodegradable polymers, polyhydroxyalkanoates (PHAs), poly-3- hydroxybutyrate (PHB), polyhydroxyvalerate (PHV), polyhydroxyhexanoate (PHH), cellulose acetate, nitro- cellulose, polylactic acid (PLA), polybutylene succinate (PBS), polycaprolactone (PCL), polyanhydrides, copolyesters, etc. Other suitable materials comprise ethylene-vinyl alcohol polymers and/or cellulose nanocrystals.

Films of polyurethane, due to its high elasticity, and of polystyrene, due to its brittleness, are found unsuitable for reliable perforation and lack robustness for use as packaging material for produce in general.

Such film may for example be a partly or fully laminated structure, or a single layer substrate, for instance multi-layer paper laminate, polymeric laminate, single layer polymeric films etc. A layer of metallization may also be provided. A laminate may be preferred for sealing and/or welding, e.g. for closing a package. This may in particular be advantageous for tray sealing packages wherein a tray may have one composition and a closing film (usually a top film) may have another composition. A laminate may be laminated fully or partly providing regions of more and less layers. The film can for example be made by extrusion processes such as blowing, casting or calendaring processes. Extrusion and/or blowing are preferred for manufacturing the film as a tubular material.

The produce may be pure, e.g. a single species of fruit or vegetable, or it may be a mixture, e.g. a mixed flower bouquet, a vegetable mixture and/or a herb mixture, etc.

Most aging processes lead to CO: production, causing a build-up in the package atmosphere. An elevated CO:- concentration may accelerate anaerobic decay processes and should be prevented. However, a too high carbon dioxide transmission rate may prevent a desired deceleration of metabolic processes and associated extension of shelf life. The presently provided ranges are preferred to meet such balance.

The packaging material of any package herein may have an oxygen transmission rate O:TR of at least 2000 ml/{m2.24 hrs), preferably at least 3000 ml/ (m?.24 hrs), more preferably at least 4000 ml/{m2.24 hrs), most preferably at least 5000 ml/{m2.24 hrs). However, an oxygen transmission rate OTR of the material may preferably be less than 15000 ml/ (m?.24 hrs), more preferably less than 10000 ml/ (m®.24 hrs), to facilitate adjustment using the one or more perforations.

Respiration and most aging processes lead to ©: consumption, causing a depletion in the package atmosphere. A high 0,TR of the packaging material and/or a high carbon dioxide transmission rate CO:TR of the packaging material facilitates fine control of oxygen influx and, respectively carbon dioxide outflow, e.g. by precisely establishing a ratio of the packaging material area and the open area of the one or more perforations to achieve the transmission ratio of the package.

Also or alternatively, the packaging material may have carbon dioxide transmission rate CO:TR of at least 15000 ml/ (m?.24 hrs), preferably at least 20000 ml/ (m?.24 hrs), more preferably at least 25000 most preferably at least 30000 ml/{(m2.24 hrs).

However, a carbon dioxide transmission rate CO:TR of the material may preferably be less than 100000 ml/ (m®.24 hrs), more preferably less than 75000 ml/{m?2.24 hrs), to facilitate adjustment using the one or more perforations.

In an aspect, a package for preserving respiring produce contained in the package, in particular vegetables, fruit, herbs, spices and/or flowers, is provided, the package defining a package volume for containing a portion of the produce and a package atmosphere, which package may in particular be a package according to any other aspect and/or embodiment discussed herein. This package comprises packaging material comprising a tray, in particular formed of or provided with a barrier material portion e.g. formed from a sheet of material comprising one or more layers comprising polyethylene terephthalate, and a lidding film sealed to the tray thus closing the package. The package has at least one of a carbon dioxide transmission rate (COsTR} of the packaging material larger than 10.000 ml/{m2.24 hrs), an oxygen transmission rate (0;TR) the material of at least 2.000 ml/{m2.24 hrs), at least one microperforation (3) provided to enable gas exchange with the atmosphere surrounding the package (1)

and to form the package into a Controlled Atmosphere Package (CAP), and a package carbon dioxide transmission rate (CO:TRpack) and a package oxygen transmission rate (O:TRpacx) providing a package transmission ratio Bpacr = CO2TRpack / O2TRpack Of at least 1,5, preferably at least 2, more preferably at least 3, still more preferably at least 4, such as 5 or more.

A tray package may protect the produce from mechanical harm and/or may collect juices leaking from the produce, thus it is particularly suitable for soft and/or liquid-producing produce like soft fruits, berries, grapes, and/or flowers. Tray packages comprising a barrier material may be particularly robust for such purposes.

Produce packaged in such tray packages according to the present concepts, may have extended shelf life. The lidding film may be a preferred location for the one or more perforations and it may have a particular influence in determining the transmission ratio of the package. E.g., the lidding film may have the specified carbon dioxide transmission rate and/or oxygen transmission rate of the material.

A tray formed from a sheet of material comprising one or more layers comprising polyethylene terephthalate (PET) may be strong and light weight. The material may be well recyclable reducing an environmental footprint. In such PET- tray, the material of each of the layers of the formed tray may comprise at least 50%, preferably at least 85%, more preferably at least 95% of amorphous polyethylene terephthalate, which facilitates forming the tray and providing high clarity of it.

The package may comprise a peripheral sealing rim provided with a layer of an adhesive along the circumference of the tray, preferably along the full circumference of the tray. The adhesive may facilitate sealing a lidding film of another (non-PET) material to the tray.

The packaging material may have a high Water Vapour Transmission Rate (WVTR), which may be in a range of 50 - 1200 ml/{m2.24 hrs). Such packaging material provides, compared to presently available packages, in particular a high transmission rate for water vapour. A high WVTR reduces humidity build-up in the package atmosphere, and in particular it reduces formation of water films and/or droplets in the package atmosphere, e.g. on surfaces within the package, such as on an inside surface of the packaging material. This reduces fungal growth and/or other decay processes. On the other hand, a too high WVTR causes decay by losing turgor, drying out and/or withering of the produce, which also is unacceptable. The presently provided values have proven to be suitable for CAP of all commercially relevant produce. A high WVTR may ensure a low water vapour concentration in the package atmosphere, reducing absorption of CO: in water and/or adverse reactions of CO; with water, in particular acid- forming.

Although a high WVTR may be generally preferred, too high WVTR may cause drying out of the produce which may be undesired. A well selected WVTR may optimise shelf life of the produce. It has been found that for several species of produce, an optimum WVTR may be desired in view of the open area of the one or more perforations to form the CAP.

The packaging material may therefore have, in particular for produce having a relatively low transpiration rate such as blueberries, chicory, grapes, pomegranate, etc., a Water Vapour Transmission Rate (WVTR) in a range of 100 - 1000 ml/{m2.24 hrs), preferably in a range of 150 - 800 ml/ (m?.24 hrs), more preferably in a range of 250- 700 ml/ (m?.24 hrs), most preferably in a range of 400 - 600 ml/ (m?.24 hrs).

In another embodiment, the packaging material may have, in particular for produce having a relatively high transpiration rate such as asparagus, avocado, peas, snap beans, mango, a Water Vapour Transmission Rate (WVTR) in a range of 100 — 1000 ml/ (m?.24 hrs), preferably in a range of 700-1100 ml/ (m?.24 hrs), more preferably in a range of 800 - 1100 ml/ (m*.24 hrs), most preferably in a range of 900 - 1000 ml/{m2.24 hrs).

A suitable packaging material may be a polymer film having a thickness in a range of 10-200 micrometres, preferably in a range of 15-150 micrometres, more preferably in a range of 20-100 micrometres, most preferably in a range of 20-75 micrometres, e.g. in a range of 25-50 micrometres such as 25-40 micrometres.

In an embodiment, the one or more perforations may comprise microperforations having an open area of below 1 square millimetre, preferably below 0.5 square millimetre, e.g. about 0.25 square millimetre or less. Such microperforations facilitate exchange of gases through the packaging material, but hinder contamination of the packed material from outside sources. Such microperforations may be made by (hot) needles. Laser perforation is an effective manner to provide such microperforations fast, reliable, food- safe, and in desired locations. Microperforations also tend not to significantly compromise integrity of the packaging material, in particular if the perforated packaging material comprises a polymeric film. Suitable films may range from a flexible films that can be bent and/or folded multiple times without harm to a rigid film for making a tray.

Laser drilled microperforations may be approximately round or oblong, having a (largest) diameter in a range of 50

— 500 micrometres, in particular in a range of 60 - 400 micrometres, preferably in a range of 90 - 300 micrometres, more preferably in a range of 100 - 250 micrometres such as in a range of 120 - 200 micrometres.

Determining an oxygen transmission rate and/or a carbon dioxide transmission rate provided by a perforation may comprise determining an open area and a film thickness. In case of a generally round, elliptical of oval perforation the open area may be determined by determining on the basis of one or more diameters determined from the hole, for which camera images may be used. A suitable calculation model is provided in Fishman et al, “Mathematical model for perforation effect on oxygen and water vapor dynamics in modified atmosphere packages”, J. Food Sci. 61(5):956-961 (1996).

The packaging material preferably is biodegradable, preferably also compostable. This reduces waste. The material may even be not only environmentally friendly but also beneficiary if it provides nutrients to the soil. Biodegradability of the material may e.g. be determined according to EN 13432 and/or ASTM D6400.

In case the packaging material is a polymer film, the polymer may be manufactured from natural produce, e.g. from maize and/or potato starch, sugars, cellulose, tapioca, etc., and/or manufactured by substantially biological processes, e.g. fermentation processes using microorganisms.

Note that in this text, “natural produce” should be understood to mean that the produce (plants, algae, etc.) lived and was harvested and processed in the present time to provide a polymer material from which the film is made, and not earth oils etc. derived from natural produce growing millennia ago.

The polymer film may be laminate or, preferably, a single-layer and/or a single-component material, which may facilitate manufacture, may produce less waste and/or be better bio-degradable and which may reduce costs. The package may contain at least one portion of respiring produce, in particular one or more vegetables, fruit, herbs, spices and/or flowers. The package may be stored with the produce kept fresh for prolonged periods. Alternatively, the package may be a wholesale package comprising plural retail portions of respiring produce. The package volume may be in a range of 2-5 times the volume of the produce in the package, in some cases in a range 3-4 times the volume of the produce in the package. In some cases the package volume may be in range of 5-10 times the produce volume, e.g. 6-8 or 7 times. A larger volume ratio may be in particular used for consumer packages and/or produce that is one or more of hollow, delicate and finely divided like raspberries, cut lettuce, herbs (parsley stalks, thymian sprigs, etc). Package volume unoccupied by produce is generally called headspace.

In view of the preceding, in an aspect a method of manufacturing a package for preserving respiring produce contained in the package, in particular vegetables, fruit, herbs, spices and/or flowers, 1s provided. The method comprises: determining from a packaging material, in particular a polymeric packaging material such as a polymer film, a portion of the packaging material to form a closed package defining a package volume for containing in the package volume a portion of the respiring produce; and determining a size, and possibly a number of one or more perforations provided in or to be provided in the packaging material to enable gas exchange between the package atmosphere and the atmosphere surrounding the package to form the package into a Controlled Atmosphere Package (CAP),

such that the package has a package carbon dioxide transmission rate CO:TR cx and a package oxygen transmission rate OsTRsacr providing a package transmission ratio Brac = CO2TRpack / O2TRpack Of at least 1,5, preferably at least 2, more preferably at least 3, still more preferably at least 4, such as 5 or more.

The method facilitates providing a package with a long shelf life.

The method may comprise determining a carbon dioxide transmission rate CO:TRmst of the portion of the packaging material and an oxygen transmission rate O:TR of the portion of the packaging material, determining a carbon dioxide transmission rate COzTRpers and an oxygen transmission rate O;TRpersr provided by the one or more perforations, and determining the package transmission ratio [ac as a ratio between the sum of the carbon dioxide transmission rates of the material and the one or more perforations and the sum of oxygen transmission rates: Ppack = (CO2TRpers + CO2TRmat) / (02TRpers + O2TRmast) - Thus, the package transmission ratio Pac: may be accurately determined.

The portion of packaging material may comprise a number m of packaging material segments, and the method may then comprise determining of each of the packaging material segments, a surface area segment Amt j; a segment carbon dioxide transmission rate CO:TRms: 3 and a segment oxygen transmission rate OzTRmat 3; and determining the carbon dioxide transmission rate of the material CO:TR and the oxygen transmission rate of the material O:TR, respectively, as a weighted sum of the respective segment carbon dioxide transmission rates CO:TRms: 3 and segment oxygen transmission rates OzTRmat 3!

CO2TR = >(j = 1.m) Amar 3 CO2TRmat 3, and, respectively, 0:TR = Z(j = 1.m) Amnat 3 O2TRmat 4. This allows accommodating and accounting for differences between packaging material segments.

The method may comprise determining of the one or more perforations a perforation carbon dioxide transmission rate CO:TRyert and a perforation oxygen transmission rate O2TRperft. Then, the perforation carbon dioxide transmission rate CO:TRsers may be determined from the perforation oxygen transmission rate O:TR‚ ers, or the other way around. However, both rates may be considered equal. The determination may comprise measuring and/or calculating from measured data.

The method may comprise: determining of each perforation of the one or more (“n”) perforations a respective perforation oxygen transmission rate O0;TRperr i and a respective carbon dioxide transmission rate COz;TRpers i; and determining the carbon dioxide transmission rate of the one or more perforations CO:TR‚erg and the oxygen transmission rate of the one or more perforations O:2TR‚erft, respectively, as a sum of the respective perforation carbon dioxide transmission rates COzTRpers i and perforation oxygen transmission rates (OzTRpers i): CO2TRpers = {1 = 1.n) CO2TRpers 3, and 02TRpers = Eli = ln) OzTRperf ;. Thus the effect of each perforation may be accurately accounted for; in particular for microperforations, small deviations from an intended size and/or shape and/or area may have significant effects for the gas transmission rate of the respective microperforation, which may have a large effect on the transmission rate of the perforations as a whole and thus for the transmission ratio of the package, in particular in case of small numbers of perforations.

The packaging material may have an oxygen transmission rate (O:TR) of at least 2000 ml/ (m?.24 hrs),

preferably at least 3000 ml/ (m?.24 hrs), more preferably at least 4000 ml/(m?.24 hrs), most preferably at least 5000 ml/ (m?.24 hrs). Also or alternatively, the packaging material may have a carbon dioxide transmission rate (CO;TR) of at least 10000 ml/{m2.24 hrs), preferably at least 12000 ml/ (m?.24 hrs), more preferably at least 15000 most preferably at least 20000 ml/ (m?.24 hrs).

To obtain the desired package the method may comprise providing the portion of the packaging material; providing the portion of the respiring produce; and forming, from the portion of packaging material and the portion of the produce the closed package.

The method further comprises providing the one or more perforations (3) in the packaging material (1A) and forming the package into the Controlled Atmosphere Package (CAP), such that the package has a package carbon dioxide transmission rate (CO:TRpack) and a package oxygen transmission rate (0:TRpack) providing a package transmission ratio Ppack = COsTRpacx / OzTRpack Of at least 1,5, preferably at least 2, more preferably at least 3, still more preferably at least 4, such as 5 or more.

In an aspect, herewith is provided a method of manufacturing a package for preserving respiring produce contained in the package, in particular vegetables, fruit, herbs, spices and/or flowers, in particular a method as described herein elsewhere, comprising providing a portion of a packaging material comprising a tray formed of or provided with a barrier material, in particular formed from a sheet of material comprising one or more layers comprising polyethylene terephthalate, and a lid sealed or to be sealed to the tray thus closing the package,

providing a portion of a respiring produce, in particular vegetables, fruit, herbs, spices and/or flowers; forming, from the portion of the packaging material and the portion of the produce, a closed package defining a package volume and containing in the package volume the portion of produce and a package atmosphere; wherein the package has at least one of a carbon dioxide transmission rate {CO:TR)} of the packaging material larger than 15000 ml/{(m2.24 hrs), an oxygen transmission rate (O;TR) the material of at least 2000 ml/{m:.24 hrs), at least one microperforation (3) provided to enable gas exchange with the atmosphere surrounding the package (1) and to form the package into a Controlled Atmosphere Package (CAP), and a package carbon dioxide transmission rate (CO2TRpack) and a package oxygen transmission rate (O:TRpack) providing a package transmission ratio Pac: = COzsTRpacr / OsTRpack Of at least 1,5. This enables providing an improved tray package.

In the method, the material of each of the layers of the formed tray may comprise at least 50%, preferably at least 85%, more preferably at least 953 of amorphous polyethylene terephthalate.

This may provide a tray that is one or more of strong, well recyclable and transparent.

Also or alternatively, the method may comprise providing the tray with a peripheral sealing rim provided with a layer of an adhesive along the circumference of the tray, preferably along the full circumference of the tray.

Although a tray and a lidding film may be welded together or otherwise sealed, an adhesive may be provided for bonding different and/or non-weldable materials together.

An aspect may comprise use of a tray formed from a sheet of material comprising one or more layers comprising polyethylene terephthalate for preserving respiring produce, in particular vegetables, fruit, herbs, spices and/or flowers, wherein the tray is provided with a lidding film formed of a gas-permeable polymer film, sealed to the tray, forming a Controlled Atmosphere Package. Such package may be a package as described herein elsewhere.

In the method, the material is provided to manufacture the package; the perforations are made to determine a predetermined transmission rate of the package for at least one atmosphere component for thus forming the package into a Controlled Atmosphere Package (CAP). In the method, the one or more perforations are determined to provide an open area to regulate inflow and/or outflow of one or more atmosphere gases, in particular introduction of oxygen into the package and/or carbon dioxide from the package.

BRIEF DESCRIPTION OF THE DRAWINGS The above-described aspects will hereafter be more explained with further details and benefits with reference to the drawing showing an exemplary embodiment.

Fig. 1 schematically shows an embodiment of an apparatus and indicates at least part of an embodiment of a method for manufacturing a package for preserving respiring produce contained in the package; Figs. 2-3 show development of concentrations of oxygen and carbon dioxide, respectively, in a CAP containing strawberries as comparative examples; Fig. 4 shows development of concentrations of oxygen and carbon dioxide, respectively, in an embodiment of a CAP containing strawberries.

DETAILED DESCRIPTION OF EMBODIMENTS It is noted that the drawings are schematic, not necessarily to scale and that details that are not required for understanding the present invention may have been omitted.

The terms "upward", "downward", "below", "above", and the like relate to the embodiments as oriented in the drawings, unless otherwise specified.

Further, elements that are at least substantially identical or that perform an at least substantially identical function are denoted by the same numeral, where helpful individualised with alphabetic suffixes.

Further, unless otherwise specified, terms like “detachable” and “removably connected” are intended to mean that respective parts may be disconnected essentially without damage or destruction of either part, e.g. excluding structures in which the parts are integral (e.g. welded or molded as one piece), but including structures in which parts are attached by or as mated connectors, fasteners, releasable self-fastening features, etc.

The verb “to facilitate” is intended to mean “to make easier and/or less complicated”, rather than “to enable”. Fig 1. shows schematically an apparatus 1 for manufacturing modified atmosphere packages 3. The apparatus 1 comprises a package forming device 5 for forming, from portions of a packaging material 7 and portions of produce 9, modified atmosphere packages 3 each defining a package volume V and containing in the package volume V a portion of produce 9 and a package atmosphere.

Here, the packaging material is supplied as a web of a packaging film 11 on a roll 13 for forming packaging portions, e.g. bags or tray lids, but other forms and types of packaging material are also possible; e.g. two or more types of packaging material may be provided, such as trays and adhesive or sealing film (not shown). Trays may be pre-provided with an adhesive and/or a welding material along a peripheral sealing rim. In Fig. 1 the produce is provided as separate portions 9 by a produce transporter 14, but other ways of providing the produce as, or into, portions 9 may be used. Here, the apparatus 1 is configured to form and fill the packages 3 and also to close and separate them in one operation. The apparatus 1 comprises an optional supply of different atmosphere modification gases to provide the package as a MAP. E.g. CO; and N;, here in the form of gas bottles 21,

23. The apparatus 1 here comprises an optional supply of pressurised air in the form of a compressor 22. The oxygen for ozone formation may be provided from a separate tank 24 as shown. The atmosphere modification gas (es) may be supplied pressurised so that they may be transported by flowing under their own pressure so that one or more propellers are not needed; however, these may be provided. Here, the device 25 comprises an optional manifold 27 connected by a gas supply conduit 31 to the package forming device 5. The manifold 27 and an optional feedback sensor signal line 33 are connected to a controller 29. As indicated in Fig. 1, the apparatus 1 further comprises a perforator, here a (possibly pulsed) laser 35 providing a (pulsed) laser beam 36, configured to provide the film 11 with microperforations. The apparatus 1 further comprises a camera 37 for imaging the microperforations and/or other control processes. The laser 35 and the camera 37 are operably connected with a perforation controller 39 for operational control, quality control and/or feedback control of the laser 35. The controller 32 may be programmable for determining one or more of the number, shape, size and position of one or more of the microperforations.

Further, not shown in any detail, the apparatus 1 may comprise a detector 41 and a calculator 43 configured to determine, e.g. by measuring and calculating on the basis of measurement results, one or more respiration properties, e.g.

an 0; consumption and/or CO:-production of the produce to be packaged and, based on that/those, determining one or more of a composition of the target modified atmosphere, a composition of the modifying atmosphere, a number and/or size of one or more microperforations (to be) made in the packaging material of the package (s).

Also, not shown, the apparatus 1 may comprise a detector and a calculator (possibly integrated into the calculator 43) configured to determine, e.g. by measuring and calculating on the basis of measurement results, a carbon dioxide transmission rate and/or an oxygen transmission rate of at least a segment of the packaging material.

EXAMPLES The following examples show the improvements provided by the present concepts.

Each example concerns a Controlled Atmosphere Package (CAP) provided by a 1 liter tray of polyethylene terephthalate (PET) provided with a lidding film sealed to the tray along the circumference of the tray, containing 400 grams of uncut strawberries (ca 0,5 liter volume).

In the package the strawberries consume oxygen and produce carbon dioxide. In the CAP, equilibrium concentrations are reached after some time, dependent on the oxygen inflow and carbon dioxide escape. For the exemplary CAP, the desired CAP equilibrium gas concentration for oxygen is 5%vol Oz, and for carbon dioxide it is 10%vol CO: at a storage temperature of 8°C. A carbon dioxide concentration [CO:] of more than 15%vol leads to damage to the strawberries and is therefore considered unacceptable.

The tray forms a barrier material providing a non- detectable, or in any case negligible, transmission rate for oxygen and for carbon dioxide. In the package the material oxygen transmission rate and material carbon dioxide transmission rate are therefore solely provided by the lidding film. In each example the lidding provides a segment surface area of 0,018 m2. The package oxygen transmission rate O:TRpack and carbon dioxide transmission rate OsTRs4ackx are therefore adjusted by one or more microperforations providing a package transmission ratio Bpack.

COMPARATIVE EXAMPLE 1 The lidding film has an oxygen transmission rate O:TR of 200 ml/{(m2.24 hrs) and a carbon dioxide transmission rate CO:TR of 600 ml/(m?.24 hrs). The material oxygen transmission is therefore O;TRyar = 200 ml/ (m?.24 hrs) x 0,018 mè = 3,6 ml/24 hrs. The material carbon dioxide transmission is therefore CO3TRpae = 600 ml/ (m?.24 hrs) x 0,018 mè = 10,8 ml/24 hrs.

In this example, the optimal oxygen equilibrium concentration of 5%vol O: is achieved with an oxygen inflow into the pack of 438 ml/24 hrs. This is achieved by providing microperforations in the package providing a perforation oxygen transmission rate of O3;TRypers = 438 — 3,6 ml/24 hrs = 434,4 ml/24 hrs, inherently yielding for the perforation carbon dioxide transmission rate CO:TRpersr = 434,4 ml/24 hrs.

Thus Bpack = (CO2TRpers + COzTRmar) / (O2TRpers + OzTRmat) = (434,4 + 10,8) / (434,4 + 3,6) = 454,2 / 438 = 1,016.

Fig. 2 shows the development of the concentrations of oxygen and carbon dioxide in the package atmosphere over a period of 10 days, starting from initial concentrations [0:] =

20.95 %vol and [CO:] = 0,04 %vol. Clearly, after only 3 days after packaging, the concentration of carbon dioxide rises over the unacceptable value of 15 %vol. Considering that packaging and transport to a reseller may well take 2 days, the package has effectively a shelf life of only 1-2 days.

COMPARATIVE EXAMPLE 2 In view of the above values of comparative example 1, in present practice, using the same lidding film, perforations are provided to keep the equilibrium oxygen concentration of 11 &vol and, more importantly, the equilibrium carbon dioxide concentration just under 15 &vol; see Fig. 3.

For this, an oxygen inflow into the pack of 773 ml/24 hrs is required, which requires providing microperforations in the package to a perforation oxygen transmission rate of O2TRpers = 773 = 3,6 = 769,4 ml/24 hrs, inherently yielding for perforation carbon dioxide CO;TRpers = 769,4 ml/24 hrs.

As a result for this case we obtain: Thus Bpack = (CO2TRpert + COzTRmat) / (OzTRpert + OzTRmat) = (769,4 + 10,8) / (769,4 + 3,6) = 780,2 / 773 = 1,009.

The resultant package prevents an unallowable excessive carbon dioxide concentration but the high oxygen level causes premature aging and allows mould growth on the product; the shelf life is therefore still limited.

EXAMPLE A lidding film is provided having a high oxygen transmission rate O;TR of 5000 ml/ (m®.24 hrs) and a high carbon dioxide transmission rate CO;TR of 60000 ml/ (m®.24 hrs).

The material oxygen transmission is therefore O>TRuar = 200 ml/ (m®.24 hrs) x 0,018 m® = 90 ml/24 hrs. The material carbon dioxide transmission is therefore CO:TRyst = 60000 ml/ (m?.24 hrs) x 0,018 mè = 1080 ml/24 hrs.

As before in comparative example 1, the optimal oxygen equilibrium concentration of 5%vol O: is achieved with an oxygen inflow into the pack of 438 ml/24 hrs. This is achieved by providing microperforations in the package providing a perforation oxygen transmission rate of O;TRpers = 438 — 90 = 348 ml/ (24 hrs), inherently yielding for perforation carbon dioxide CO;TRperr = 348 ml/ (24 hrs). Thus Bpack = (CO2TRpers + COsTR) / (02TRpers + OsTR) = (348 + 1080) / (348 + 90) = 1429 / 438 = 3,263. Fig. 4 shows that, indeed, the equilibrium oxygen concentration of 5 %vol is achieved and that the equilibrium carbon dioxide concentration is about 11 %vol, well under 15 Zvol. Such package may have a shelf life of well over a week. It should be noted that for this perforation oxygen transmission rate of O2TRsers = 348 ml/24 hrs, compared to O2TRpers = 438 ml/24 hrs of comparative example 1, about 303 fewer or smaller microperforations need be provided in the packaging material and compared to O:TRpers = 773 ml/24 hrs of example 2 about 55% fewer or smaller microperforations. The disclosure is not restricted to the above described embodiments which can be varied in a number of ways within the scope of the claims. For instance elements and aspects discussed in relation to a particular embodiment may be suitably combined with those of any other embodiment.

Claims

CONCLUSIONS

A package for storing in the package a breathable product, in particular vegetables, fruits, herbs, spices and/or flowers, the package defining a package volume for containing a portion of the product and a package atmosphere, and comprises a packaging material, in particular a polymer film (1A), provided with one or more perforations (3) that allow gas exchange with the atmosphere around the packaging (1) to form the packaging into a Controlled Atmosphere Package (CAP); wherein the package has a carbon dioxide permeability (CO:2TRpack) and an oxygen permeability (OzTRgacr} and a package permeability ratio Bpacr = CO2TRpack/O02TRpack of at least 1.5, preferably at least 2, more preferably at least 3, with even more preferably at least 4, such as 5 or more.

A package according to claim 1, wherein the atmosphere of the package defines an equilibrium amount of oxygen and an amount of carbon dioxide that together make up less than 20% vol of the package atmosphere.

The package according to any one of the preceding claims, wherein the one or more perforations (3) provide a perforation carbon dioxide permeability (CO:TRgerf} and a perforation oxygen permeability (O2TR.rf) such that the package carbon dioxide permeability (CO: TR acer) is the sum of the perforation carbon dioxide permeability (CO:TRypers) and the material carbon dioxide

permeability of the (COsTRmat) of the packaging material (COzTRpacx = COsTRgerg + CO:TRmat) and the packaging oxygen permeability (O:TRpacx) is the sum of the perforation oxygen permeability (O°TRgerf) and the material oxygen - permeability (O2TRmat) of the packaging material (O:TRpack = O0:TRpers + O2TRmat) and the packaging-permeability ratio Brac: iS Bpack = (CO2TRpert + CO2TRuat) / (OzTRperr + OzTRmat) .

The package according to any one of the preceding claims, wherein the packaging material encloses the packaging volume defining a packaging volume area Apacx, the packaging material comprising a plurality (m) of packaging material segments each having a respective segment area Amnat ; define having a respective segment carbon dioxide permeability (CO2TRmat 3) and a segment oxygen permeability (O2TRmat 3), wherein the material carbon dioxide permeability (CO:TRuat) is the weighted sum of the respective segment carbon dioxide permeability (CO:TRmat 3) and the material - oxygen permeability {(O2TRuar) is the weighted sum of the respective segment oxygen permeabilities (O2TRmat 3): COzTRmat = 1 (J = 1.Mm) Agar 3 CO2TRmat 5, and O2TRuar = Zj = 1m) Anst 5 OoTRmat 5.

The packaging according to any one of the preceding claims, wherein the packaging material has an oxygen permeability (O:TR)}) of at least 2000 ml/{m2.24 hours), preferably at least 3000 ml/{m2.24 hours),

more preferably at least 4000 ml/(m2.24 hours), most preferably at least 5000 ml/(m2.24 hours) and/or wherein the packaging material has a carbon dioxide permeability (CO;TR) of at least 15000 ml/(m*.24 hours), preferably at least 20000 ml/{m2.24 hours), more preferably at least 25000, most preferably at least 30000 ml/{m2.24 hours).

6. A package for storing breathable products contained in the package, in particular vegetables, fruits, herbs, spices and/or flowers, wherein the package defines a package volume for containing a portion of the product and a package atmosphere, wherein the packaging is in particular a packaging according to any one of the preceding claims, wherein the packaging comprises packaging material comprising a tray, in particular formed from or provided with a barrier material part formed for instance from a sheet of material comprising one or more layers comprising polyethylene terephthalate, and a cover foil that is sealed to the tray and thus closes the package, wherein the package has at least one of a carbon dioxide permeability (CO:TR} of the packaging material greater than 10,000 ml/(m?. 24 hours), an oxygen permeability (OsTR) of the packaging material of at least 2,000 ml/{m2.24 hours), provide at least one microperforation (3) n to allow gas exchange with the atmosphere around the package (1) and to form the package into a Controlled Atmosphere Package (CAP), and a package carbon dioxide permeability (CO;TRpack) and a package oxygen permeability (0;TRpack) which have a package permeability ratio Bpacr = CO2TRpack/02TRpack of at least 1.5.

The package according to claim 6, wherein the material of each of the layers of the formed tray comprises at least 50%, preferably at least 85%, more preferably at least 95% amorphous polyethylene terephthalate and/or wherein the package comprises a sealing edge circumferentially provided with a layer of adhesive along the perimeter of the tray, preferably along the entire perimeter of the tray.

The package according to any one of the preceding claims, containing breathable product in the package, in particular one or more vegetables, fruits, herbs, spices and/or flowers.

A method for manufacturing a package for storing a breathable product contained in the package, in particular vegetables, fruit, herbs, spices and/or flowers, comprising determining a packaging material, in particular a polymeric packaging material such as a polymer film, a portion of the packaging material to form a closed package defining a package volume to contain in the package volume a portion of the breathable product; and determining a size and optionally a number of one or more perforations (3) provided in or to be provided in the packaging material (1A) to allow gas exchange between the packaging atmosphere and the atmosphere surrounding the packaging (1) to packaging into a Controlled Atmosphere Package (CAP), such that the packaging has a packaging carbon dioxide permeability (CO;TRgack) and a packaging oxygen permeability {(O2TRpack}) that has a packaging permeability ratio Brack = CO2TRpacr /OzTRpack of at least 1.5, preferably at least 2, more preferably at least 3, even more preferably at least 4, such as 5 or more.

A method according to claim 9, comprising determining a carbon dioxide permeability COsTRmst of the portion of the packaging material and an oxygen permeability OsTRmm: of the portion of the packaging material, determining a carbon dioxide permeability CO2TR press provided by the one or more perforations (3) and an oxygen permeability OsTRerr provided by the one or more perforations (3), and determining the package permeability Bac: as a ratio between the sum of the carbon dioxide permeability of the material and of the one or more perforations and the sum of the oxygen permeability of the material and of the one or more perforations: Bpacr = (CO:TRpers + COsTRmat) / (OsTRpert + OoTRmat) .

The method of any one of claims 9-10, wherein the portion of packaging material comprises a plurality (m) of packaging material segments, and the method comprises determining each of the packaging material segments, a surface segment Amar j; a segment carbon dioxide permeability (COsTRma: j} and a segment oxygen permeability (O:TRmat 4); and determining the carbon dioxide permeability of the material (CO:zTRmat) and the oxygen permeability of the material {(OsTRuat), respectively, as a weighted sum of the respective segment carbon dioxide permeabilities (CO2TRmar 3) and segment oxygen dioxide permeabilities (OzTRmat 5): COzTR = 3 (3 = 1.m} Amst 3 COzTRmat 35 and 0:TR = T(J = l.m) Anat 4 O2 TRpac 4.

A method according to any one of claims 9-11, comprising determining the one or more perforations (3) a perforation carbon dioxide permeability (COsTRerr) and a perforation oxygen permeability (OzTRserf) wherein the perforation carbon dioxide permeability ( CO:TRpers) can be determined from perforation oxygen permeability (O2TRperr) » Or vice versa.

A method according to any one of claims 9-12, comprising determining each perforation (3:; 1 = 1 ... n) of the one or more perforations (3) a respective perforation oxygen permeability (O2TRrert 3) and a respective carbon dioxide permeability (CO2TRperf 3) and determining the carbon dioxide permeability of the one or more perforations (CO:TRper:) and oxygen permeability of the one or more perforations (0;TRpers), respectively, as a sum of the respective perforation carbon dioxide permeability (CO2TRpers ij and perforation oxygen permeability (Oz2TRpert i): COzTRpers = (1 = 1.n) COzTRpers i, and O2TRpers = Eli = 1.n) OsTRperf i-

A method according to any one of claims 9-13, wherein the packaging material has an oxygen permeability (OTR) of at least 2000 ml/{m2.24 hours), preferably at least 3000 ml/{m2.24 hours), more preferably at least at at least 4000 ml/{m:.24 hours), most preferably at least 5000 ml/(m?.24 hours) and/or wherein the packaging material has a carbon dioxide permeability (CO;TR) of at least 10000 ml/ {(m 2 . 24 hours), preferably at least 12000 ml/{(m 2 %, 24 hours), more preferably at least 15000, most preferably at least 20000 ml/{m 2 .24 hours).

A method according to any one of claims 9-14, comprising: providing the portion of the packaging material; providing the portion of the breathable product; forming, from the packaging material part and the product part, the closed packaging; the method comprising providing the one or more perforations (3) in the packaging material (1A) and forming the packaging into the Controlled Atmosphere Package (CAP) such that the packaging has a packaging carbon dioxide permeability (CO2TRpack) and a packaging - oxygen permeability (O2TRpaex)

which provide a packaging permeability ratio Bpac:=CO2TRpack/O2TRpack of at least 1.5, preferably at least 2, more preferably at least 3, even more preferably at least 4, such as 5 or more.

A method for manufacturing a package for storing a breathable product contained in the package, in particular vegetables, fruit, herbs, spices and/or flowers, in particular a method according to any one of claims 9-15, comprising providing a portion of a packaging material comprising a tray formed from or provided with a barrier material, in particular formed from a sheet of material comprising one or more layers comprising polyethylene terephthalate, and a lid which is or is to be sealed to the tray thus closing the package, providing a portion of a breathable product, in particular vegetables, fruits, herbs, spices and/or flowers; forming, from the packaging material portion and the product portion, a closed package defining a packaging volume and containing in the packaging volume the product portion and a packaging atmosphere; wherein the packaging has at least one of a carbon dioxide permeability (CO,TR) of the packaging material greater than 15000 ml/(m?. 24 hours), an oxygen permeability (OsTR)}) of the material of at least 2000 ml/{({ m?2.24 hours), at least one microperforation (3) provided to allow gas exchange with the atmosphere surrounding the package (1) and to form the package into a Controlled Atmosphere Package (CAP), and a package carbon dioxide permeability (CO :TRpaer) and a packaging oxygen permeability (OzTRpacxx) having a packaging permeability ratio Bpacr = CO:TRpack/02TRpack of at least 1.5.

A method according to claim 16, wherein the material of each of the layers of the formed tray comprises at least 50%, preferably at least 85%, more preferably at least 95% amorphous polyethylene terephthalate and/or wherein the method comprises providing of the tray with a sealing edge along the periphery which is provided with a layer of adhesive along the perimeter of the tray, preferably along the entire perimeter of the tray.

Use of a tray formed from a sheet of material comprising one or more layers of polyethylene terephthalate for the storage of breathable product, in particular vegetables, fruits, herbs, spices and/or flowers, the tray being provided with a cover foil formed from a polymer film provided with one or more micro-perforations, sealed to the tray, forming a Controlled Atmosphere Package, in particular a package according to any one of claims 1-8.